Means for applying spray materials



2 Sheets-Sheet 1 A... .l ,/ff/l l l 2.....111 ...22.1. ...L- I. t a l .f

- INVENTOR.

Ml J BEPTJM f l .i BY

H5 ATTORNEY Oct. l6, 1936. m.v s. RoBERTsoN MEANS FOR APPLYING SPRAYMATERIALS Filed April 25 1934 Oct. 6, 1936. M. s. ROBERTSON MEANS FORAPPLYING SPRAY MATERIALS Filed April 25, 1954 2 sheets-sheet 2 lINVENTOR. Aff/70N 5'- EKU? 501V- BY M v H/ A TTORNEY Patented Oct. 6,1936 UNITED STATES PATENT OFFICE MEANS Foa ArPLYmG SPRAY MATERIALSMilton S. Robertson, Alameda, Calif., assignor to Independent CropDusting Inc., San Francisco, Calif., a corporation of CaliforniaApplication April 25, 1934, Serial No. '122,222 11 Claims. (Cl. 299-38)My invention relates to the application of spray materials, and moreparticularly to the application of materials from airplanes for suchuses the control of pests over infected areas or for controlling fireareas.

A more specific object of my invention is to provide apparatus fortreating crops from airplanes by which the treating material is appliedto the under surfaces as well as the top surfaces of the crop foliage.

Another object of my invention is to provide means for effecting thebetter coverage with no greater cost per acre than that required in cropdusting.

Another object of my invention is to provide means of the characterdescribed which will handle a wide variety of spray liquids.

Another object of my invention is to provide-a system of spraying whichutilizes air for diluting a concentrated spray material.

Further objects include the provision of apparatus of the characterdescribed which is of light weight, low power consumption,self-cleaning, adapted to resist the stresses imposed by flightconditions, and designed to eliminate interference with planemaneuvering and control.

The invention possesses other objects and features of advantage, some ofwhich, with the foregoing, will be set forth in the followingdescription of my invention. It isvto be understood that I do not limitmyself to this disclosure of species of my invention, as I may adoptvariant embodiments thereof within the scope of the claims.

Referring to the drawings:

Figure 1 is an axial sectional view of my improved spray apparatus,portions of the drive shaft and housing being omitted to shorten theview. I

Figure 2 is a bottom view of an airplane show- 40 ing a method ofmounting my apparatus.

Figure 3 is a transverse vertical sectional view taken in a plane alongthe line 3--3 of Figure 1, and shows the forward bracket mounting.

Figure 4 is a transverse vertical sectional view 45 taken in a planealong the line 4-4 of Figure l, and shows the spray distributing headassembly with portions of the brushes and spacing disks broken away todisclose their construction and 50 positional relationship,

Figure 5 is a transverse vertical sectional view taken in a plane alongthe line 5 5 of Figure l, and shows the valve assembly with portions ofthe outer valve plate broken away to disclose the inner plateconstruction.

Figure 6 is` a detail view showing the inner face of the outer valveplate.

Figure '7 is a vertical sectional view taken in a plane indicated by theline I--l of Figure 5, and shows the valve control mechanism. 5

In terms of broad inclusion, the apparatus embodying my inventioncomprises a rotatable distributing head mounted on the plane forreducing and dispersing the spray material. Power for driving thedistributing head is preferably derived 10 from a propeller mounted onthe plane and rotatably connected with the head. The distributingheadcomprises a porous rotor having a hollow core; an annular brushhaving radially extending bristles being preferably used. Means 15 areprovided for feeding the material to be sprayed into the core of thebrush, and impeller means are preferably provided for driving thematerials under pressure between the bristles of the brush. 20

In greater detail, and referring particularly to Figures 1 and 2 of thedrawings, the spray apparatus embodying my invention comprises a shaft 2journaled in a, bearing tube 3 and arranged to extend longitudinally ofan airplane 4. 25 A propeller 6 is mounted on the leading end of theshaft 2, and a distributing head I is mounted on the trailing end of theshaft. The spray unit is preferably suspended under the airplane wing,and suitable brackets 8 are preferably provided 30 for the mounting. Oneor more of these units may be provided. Two units are shown in Figure 2,one mounted on each side of the fuselage, but it is understood that thisis merely for purposes of illustration.

As best shown in Figure 1, the shaft 2 is journaled in suitable bearings9 mounted in bearing stations spaced along the bearing tube 3. Thebearing stations reenforce the tube and space the bearings from thelatter so that the bearings may 40 be easily withdrawn from the tube. Athrust collar I0 is provided behind the rear bearing, and spacing tubesII are preferably provided for holding the bearings in position. Thepropeller 8 Is locked to the shaft by a suitable key I2, and ispositioned between a. pair of sleeves I3 and I4; the inner sleeve I3projecting into the bearing tube 3 to space the propeller from theforward bearing 9. The whole is then held together by a nut I6 threadedon the end of the shaft. A pack- 50 ing I'I is interposed between thesleeve I3 and the bearing tube, and is held between a pair of retainerrings I8 and compressed by a nut I9 surrounding lthe sleeve and threadedon the end'of the tube. This packing operates to seal the bear- The rearend 20 of the bearing tube is preferably reduced to provide a shoulderadjacent the forward bearing 9, and this end of the tube is sealed by apacking 2| compressed between a bushing 22 and a nut 23 threaded on thereduced portion of the tube.

The rear portions of the bearing tube project into a casing 24. Thiscasing is provided with an inlet duct 26 and forms a chamber forreceiving the spray liquid. 'I'he forward end of the casing is providedwith a neck portion 21 fitted on the bearing tube, and this end of thecasing is sealed by a packing 28 held by a nut 29 surrounding the tubeand threaded on the neck portion of the casing. This arrangement forms asealed joint between the casing and bearing tube and at the same timeprovides a degree of flexibility between these elements.

'Ihe rear end of the bearing tube is supported in the casing by a plateor disk 3l mounted on the reduced portion 20 of the bearing tube andheld by a nut 32 threaded on the tube. The nut is preferably split andprovided with a screw 33 so that it may be locked to the threads. Awasher is preferably interposed between the nut 32 and plate 3|, and isprovided with a spring finger 34 engaging flutes on the packing nut 23for holding the latter in a selected position of adjustment. Theperipheral portions of the plate 3| are preferably grooved to provide aseat for the rear end of the casing 24, and the plate is secured by aretainer bell 36 threaded on the casing and abutting the plate.

The spray fluid introduced into the casing 24 through the duct 26 is fedrearwardly by a valve mechanism of which the plate or disk 3| comprisesa part. The latter disk is locked against rotation by a pin 31projecting into the bearing tube, and is further locked by a key 36formed on the casing and engaging a socket 39 cut in the peripheralportions of the disk. Note Figure 6. As also shown by the latter figure,the fixed plate 3| is provided with a series of valve apertures 4|.

The movable portion of the valve mechanism comprises a second disk 42journaled on the bearing tube 3 immediately ahead of the fixed plate 3|.The movable plate 42 is provided with valve apertures 43 adapted to moveinto registration with the apertures 4| of the fixed plate. Theapertures of both valve plates are preferably arcuately shaped, asshown. This shape of aperture will pass a large quantity of fluid in thewide open position and at the same time will permit a gradual openingand cut off to give the operator accurate control over the liquid flow.Movement of the plate 42 is limited by a slot 44 cut in its peripheryand engaging the key 38 of the casing. The mov-able valve plate is heldtightly against the fixed plate by a spring 46 compressed between theforward end of the casing and a sleeve 41 slidable on the bearing tubeand bearing against the movable plate.

As best shown in Figure 7, the position of the movable valve plate iscontrolled by mechanism comprising a plunger 48 slidable in a tube 48threaded in the casing 24, and carrying a pin 5| projecting into a seat52 provided in the valve plate. The eccentric arrangement of the plungerwith respect to the disk, as better lshown in Figure 5, causes the diskto rotate when the plunger is reciprocated, as will be readilyunderstood. The position of the plunger 48 is controlled by a yoke 53having a follower'- roller 54 ing tube so that the latter will retain alubricant.

riding on a cam 56. The yoke is connected to the plunger by a rod 51projecting downwardly into the tube- 46 and threaded into the plunger.The casing is sealed at this point by a packing 58 compressed between abushing 59 and a packing nut 6| threaded on the tube 49.

The position of the valve disk is such that the valve is closed when theplunger 48 is in its down position, the valve being held normally closedby a spring 62 surrounding the rod 51 and bearing against the plunger48. Adjustment to time the opening -of the valve with respect to themovement of the cam is .effected by screwing the rod 51 into or out ofthe plunger 48. As best shown in Figures 1 and 5, the cam 56 is mountedon a shaft 63 journaled in supports 64 formed on the bracket mounting66. Where a plurality of units are provided, as shown in Figure 2, thecam shaft is extended to carry the cams of the several units. Movementof the cam shaft is controlled by a lever 61 connected with a suitablelever in the pilots compartment by a connecting rod 68.

'I'he distributing head for reducing the spray material to a finelydivided state of subdivision carried on the rear end of the shaft 2.Referring again to Figure l, the distributing head preferably comprisesa hollow rotor mounted on the end of the shaft 2 with a. neck or mouthportion 1| slidable within the rear end of the retainer bell 36. Thisjoint between the bell and rotor is sealed by a packing 12 held by apacking nut 13 threaded on the bell. The hub 14 of the rotor ispreferably tapered to fit a complementary tapered portion of the shaft,and is held by a nut 16 threaded on a reduced end of the shaft. A washer11 having outturned lips for eng-aging the rotor and nut respectively ispreferably interposed between these elements so that any tendency towardrelative rotation causes the nut to tighten and force the rotor moretightly on the shaft. A cupped nut 18 threaded on the shaft and seatedover the nippled end of the nut 16 operates to lock the latter.

As best shown in Figure 4, a plurality of radially extending ns orlmpellers 18 are provided in the rotor. By this arrangement the rotor isin effect a centrifugal pump, and when the shaft is rotating theimpellers operate to draw the fluid through the mouth 1| and throw thesame radially of the rotor. A porous casing is provided about theimpeller blades for subdviding the fluid and dispersing the resultingminute particles in the surrounding atmosphere. This porous casingstructure enclosing the impellers is mounted for rotation with thelatter, and preferably comprises a plurality of circular wire brushes 8|having radially extending bristles. The brushes are of the hollow coretype with the base portions of the bristles clamped between retainingrings 82.

The brushes are preferably separated by spacing disks 83, and the wholeassembly is secured together by suitable screws 84 passing through acompression flange 86 and threaded into a buttress flange 81 on therotor. In order to prevent relative rotation the compression flange 86is provided with lip portions 88 projecting inwardly between theimpeller blades 19. The rear end of the rotor is sealed by means of ahub cap 89 threaded on a rearwardly extending neck portion of thecompression flange 86.

When the rotor is rotating and fluid is fed into the open core of thebrushes, centrifugal force tends to drive the fluid outwardly throughthe brushes 8|. This outward driving of the fluid is :almaar of courseassisted by the action of impeller blades lil, vas will be readilyunderstood. ".i'he entrance of the fluid into the porous structure ofthe brushes is facilitated by apertures or i'e eesses 9i extendingradially in the spacing plates 33. These recesses provide open passagesbetween the brushes, and serve to conduct the fluid past the compressedbase portions of the brushes and into the open fiber structure. Onceintroduced between the bristles the fluid passes outwardly along thebristles and is thrown radially from the peripheral portions of thebrushes.

By this mechanism the fluid is thoroughly broken up, and is thrown fromthe distributing head in minute liquid particles. The dispersion ofthese liquid particles in the air creates a light fog or mist, whichwill readily follow the course of disturbed air currents.

The spray material is fed to the spray units by suitable ducts 92leading from a common tank 93 preferably mounted in the fuselage of theplane. Note Figure 2. If desired, a shut-off valve may be provided inconnection with the tankSl for cutting off the fluid from the units.`Such a valve of course would be secondary tolthose in the separateunits.

In use, the pilot operating the plane makes his flight over the croparea to be treated in a manner similar to that now practiced in cropdusting. As the plane travels over the ground it creates a downwarddraft which is known in the art as down wash. This downdraft compressesthe air in a strata. adjacent the ground and enveloping the crop. Afterthe plane passes, and the source of the downdraft thereby removed, theair in the compressed strata expands to create a nal upward current. Ifthe spray material is introduced into this downdraft it will be carrieddownwardly to Wet the upper surfaces of the crop foliage in a mannersimilar to the deposit of dust on the upper in the process of cropdusting. The added feature of my process however is to take advantage ofthe final upward air movement during expansion of the compressed airstrata to carry the spray material 'into contact with the under surfacesof the crop foliage.

This is accomplished by reducing the liquid to such a finely dividedstate of subdivision that it remains suspended in the air until afterthe period of expansion and upward air movement. I have found that thedistributing head of my spray apparatus produces a fog or mist in whichthe particles are held suspended for the desired period of time. Byactual tests it has been found that the under surfaces as well as thetop surfaces of the crop foliage are thoroughly wetted. Being of liquidnature the spray material adheres to the under surfaces.

The spray apparatus of my invention will deliver the large quantities offluid necessary for coverage by airplane application, and will handlethe heavier as well as the lighter fluids. The apparatus has been usedto apply water solutions, paste emulsions, oils, oil suspensions, andother combinations of liquids and suspended solids. The apparatus isadapted for use with gaseous as well as liquid fluids. The spraymaterial employed may be in a highly concentrated form, because thethorough breaking up of the material and distribution in the airoperates toA dilute the material. The large quantities of diluting waterordinarily used in spray methods therefore become unnecessary.

A very accurate control of liquid particle size is had by thedistributing head of my invention.

By dispensing with the Spacing disks entirely, and using the brushesonly, an extremely finely divided spray will result. By the spacingdisks to facilitate the liquid passage into the outer and more openportions of the brush structure, a heavier mist is produced. Stillheavier fog-like particles may be produced by increasing the number orthickness of the disks. The latter of course would be desirable inconjunction with the heavier liquids. Where little breaking up of theliquid is necessary, such as is the case where oil is coated over marshareas for mosquito control, both the brushes and spacing to bedischarged directly into the atmosphere from the pump impellers.

Other advantages of my improved apparatus are that it is of lightweight, low in power consumption, and is substantially self-cleaning.Furthermore, the degree of flexibility provided in the units adapts themto resist the stresses imposed by ight conditions. Still further, aplane equipped with apparatus of my invention feels little interferencein maneuvering and control. The latter is due to the light weight of therotating head and the consequent low gyroscopie action of the apparatus.'I'his not only minimizes the interference with maneuvering, but alsoren duces the stresses in the unit itself. A feature of the light weightof the apparatus as a whole is that the units may be mounted out closeto the tips of the wings, which has the advantage of introducing thespray material in the disturbed air currents at these points. Thesecurrents are known as "tip vortici and have a. turning motion which aidsto increase and give a. more uniform wetting over the Width of theswath.

It is understood of course that the principles embodied in my improvedspray distributor head may be incorporated in other types of apparatus.For example, the head may be incorporated in spray apparatus for use onthe ground. The ability of the head to discharge large quantities offinely divided spray material in the atmosphere and without creating aheavy blast of the material makes it especially suitable for groundwork. The ideal condition for good coverage is a slow moving air currentheavily saturated with minute particles of the spray material, and thisis just what is secured by my distributor head.

It is also understood that the porous casing structure about theimpeller blades vof the distributor head may be of a. structure otherthan brushes. lFor example, a series of screen disks could be employed,placed side by side to build up the porous ring structure. The desiredcharacteristic in this casing about the impellers is its porosity, sincethe multiplicity of intercommunicating passages provided thereby, andthrough which the spray fluid must pass `to reach the periphery of thespray wheel, perform the function of reducing the fluid to the desiredstate of finely divided subdivision.

I claim:

1. Spray apparatus comprising s. plurality o circular brushes having ahollow core, means for spacing the brushes to provide passages bedisksmay be dispensed with, allowing the oil tween the core and theintermediate portions of a plurality of annular brushes mounted Aon theperipheral portions of said impellers, disks for spacing said brushesvand having apertures providing passages betweensaid impellers and theintermediate portions of said brushes, means for rotating the shaft, andmeans for feeding material to be sprayed to said impellers.

3. Spray apparatus comprising a shaft, a plurality of impellers radiallymounted on the shaft, an annular porous member mounted on the peripheralportions of said impellers, means for rotating -the shaft, and means forfeeding material to be sprayed to said impellers.

4. Spray apparatus comprising a shaft, a plurality of impellers radiallymounted on the shaft, a plurality of annular porous members mounted onthe peripheral portions of said impellers, means for spacing saidmembers, means for rotating the shaft, and means for feeding material tobe sprayed to said impellers.

5. The combination with an airplane having a fuselage and wing, of aspray apparatus comprising a distributing head, and means for mountingthe head beneath the wing in a position laterally spaced from thefuselage and adjacently behind the trailing edge of the wing.

6. Spray apparatus comprising a bearing tube. a distributing headadjacent one end of the tube, a shaft in the tube for driving the head,bearings for the shaft and insertably mounted in the tube, and means onth-e shaft for holding the bearings in spaced relation.

7. Spray apparatus comprising a bearing tube, a shaft journaled in thetube and projecting therefrom, a distributing head mounted on theprojecting end of the shaft, a casing mounted on the end of the bearingtube and connected with the distributing head for feeding spraymaterialto the distributing head, and means for sealing the end of thebearing tube against the entrance of the spray material.

8. Spray apparatus comprising a duct for spray material, a hollowdistributing head rotatably mounted on the duct, a packing gland forsealing the rotor connection between said head and duct,

radially extending impellers in the head, and means for driving thehead. y y

9. Spray apparatus comprising a duct for spray material, a shaft,' adistributing head on the shaft and rotatably mounted on the duct,impellers in the head, and a propeller on the shaft for driving thehead.

10. Spray apparatus comprising a shaft, a hollow cylindrical rotormounted on the shaft, a

plurality of annular brushes mounted on the peripheral portions of therotor, spacers between the brushes, impellers in the rotor, means forrotating the shaft, and means for feeding material to be sprayed to theimpellers.

11. Spray apparatus comprising a plurality of annular brushes arrangedside by side, means for rotating the brushes about their central axis,

